1. Field of the Invention
The present invention relates to a scanning exposure apparatus and an exposure method, for example suitably applicable to exposure of large-area patterns on a photosensitive substrate used for fabricating liquid crystal display devices.
2. Related Background Art
Conventional exposure apparatus for exposure of large-area patterns of this kind include those of scanning types such as the step-and-repeat type for repetitively projecting small transfer images of mask through a single projection optical system onto the photosensitive substrate or the mirror projection type for projecting transfer images at magnification of unity to mask as obtained by an arc slit illumination beam through a single projection optical system onto the photosensitive substrate.
On the other hand, it is considered that a plurality of projection optical systems are arranged instead of the single projection optical system. Namely, exposure apparatus of this type are so arranged that light beams emitted from a plurality of illumination optical systems illuminate a plurality of small regions on the mask. Transfer images of these plural small regions are simultaneously projected through respective projection optical systems onto the photosensitive substrate.
As shown in FIG. 6, the transfer images P1-P5 of plural small regions are transferred as separated into a first series of transfer images including the transfer images P1, P3, and P5 and a second series of transfer images including the transfer images P2 and P4. The direction of the first series of transfer images is approximately perpendicular to the scanning direction (hereinafter referred to as the X direction) of the mask and photosensitive substrate and parallel to the Y direction within the plane of photosensitive substrate. The transfer images P1, P3, and P5 are arranged with separations 2Ly between the centers thereof. Also, the direction of the second series of transfer images is parallel to that of the first series of transfer images, and the transfer images P2 and P4 are arranged with a separation 2Ly between the centers thereof. Then, these transfer images P1-P5 are transferred by scanning in the X direction while partly overlapping in the Y direction. By this, large-area patterns are projected onto the photosensitive substrate when the mask and the photosensitive substrate are synchronously scanned.
The present invention concerns a scanning exposure apparatus which comprises a plurality of illumination optical systems each for illuminating a plurality of regions M1-M5 on a mask with a pattern formed thereon, a first optical system having a plurality of projection optical systems optical axes of which are arranged in a line along a first direction Y, and a second optical system having a plurality of projection optical system which are arranged in parallel with the first optical system and optical axes of which are arranged in a line a predetermined distance D apart from that of the first optical system, in which some P1, P3, P5 of images P1-P5 of the plurality of regions M1-M5 and the rest P2, P4 of the images P1-P5 are simultaneously projected through the first optical system and through the second optical system, respectively on the photosensitive substrate, in which the mask and the photosensitive substrate are synchronously scanned in a direction X approximately perpendicular to the first direction Y and in the plane of photosensitive substrate, and which is further provided with rotating means for effecting relative rotation between the mask and the photosensitive substrate in the plane of mask or photosensitive substrate, position changing means for changing relative positions of the mask and the photosensitive substrate in the first direction Y in accordance with a position in the scanning direction X, of the mask or photosensitive substrate, and image position changing means for relatively changing positions of the images P1, P3, P5 projected through the first optical system and positions of the images P2, P4 projected through the second optical system in the first direction Y.
It is preferred that the image position changing means be arranged to effect the relative change, based on a deviation of angle of a first coordinate system concerning an arrangement of the pattern formed on the mask with respect to a second coordinate system determined by the scanning direction X and the direction Y perpendicular to the scanning direction X.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, positions of the second images are relatively changed based on a deviation of angle of a first coordinate system concerning an arrangement of the first images with respect to a second coordinate system determined by the scanning direction X and the direction Y perpendicular to the scanning direction.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, positions of the second images are relatively changed based on a deviation of angle of a first coordinate system concerning an arrangement of the pattern of mask with respect to a second coordinate system concerning an arrangement of the first images.
Also, the present invention relates to a scanning exposure apparatus which comprises a plurality of illumination optical systems each for illuminating a plurality of regions M1-M5 on a mask with a pattern formed thereon, a first optical system having a plurality of projection optical systems optical axes of which are arranged in a line along a first direction Y, and a second optical system having a plurality of projection optical systems which are arranged in parallel with the first optical system and optical axes of which are arranged in a line a predetermined distance apart from that of the first optical system, in which some P1, P3, P5 of images P1-P5 of the plurality of regions M1-M5 and the rest P2, P4 of the images P1-P5 of the plurality of regions M1-M5 are projected through the first optical system and through the second optical system, respectively, onto the photosensitive substrate, and in which the mask and the photosensitive substrate are synchronously scanned in a direction X approximately perpendicular to the first direction Y and in the plane of photosensitive substrate. The apparatus is provided with image position changing means 9A-9E for changing, by a predetermined angle, arrangement directions of the images P1-P5 projected through the first optical system and the second optical system relative to the first direction Y, changing intervals 2Ly between the images P1, P3, P5 projected through the first optical system and an interval 2Ly between the images P2, P4 projected through the second optical system, and changing positions of the respective images P1-P5 in a rotational direction with respect to the optical axis.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, the image position changing means performs the changing of arrangement directions, the changing of image intervals, and the changing of positions in the rotational direction, based on a deviation of angle of a first coordinate system concerning an arrangement of the first images with respect to a second coordinate system determined by the scanning direction X and the direction Y perpendicular to the scanning direction X.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, the image position changing means performs the changing of arrangement directions, the changing of image intervals, and the changing of positions in the rotational direction, based on a deviation of angle of a first coordinate system concerning an arrangement of the pattern with respect to the second coordinate system concerning an arrangement of the first images.
An exposure method according to the present invention is carried out by an apparatus comprising a plurality of illumination optical systems each for illuminating a plurality of regions M1-M5 on a mask with a pattern formed thereon, a first optical system having a plurality of projection optical systems optical axes of which are arranged in a line along a first direction Y and a second optical system having a plurality of projection optical systems which are arranged in parallel with the first optical system and optical axes of which are arranged in a line a predetermined distance apart from that of the first optical system, in which some P1, P3, P5 of images P1-P5 of the plural regions M1-M5 and the rest P2, P4 of the images P1-P5 of the plural regions M1-M5 are projected through the first optical system and through the second optical system, respectively, onto the photosensitive substrate and in which the mask and the photosensitive substrate are synchronously scanned in a direction X approximately perpendicular to the first direction Y and in the plane of photosensitive substrate, said exposure method comprising a rotating process for relatively rotating the mask and the photosensitive substrate within the plane of mask or photosensitive substrate, a position changing process for changing relative positions of the mask 1 and the photosensitive substrate 8 in the first direction Y in accordance with a position of the mask or photosensitive substrate in the scanning direction X, and an image position changing process for relatively changing positions of the images P1, P3, P5 projected through the first optical system and positions of the images P2, P4 projected through the second optical system in the first direction Y.
It is preferred that the image position changing process be arranged to effect the relative change, based on a deviation of angle of a first optical system concerning an arrangement of the pattern formed on the mask with respect to a second coordinate system determined by the scanning direction X and the direction Y perpendicular to the scanning direction X.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, the image position changing process is to effect the relative based on deviation of angle of a first coordinate system concerning an arrangement of the first images with respect to a second coordinate system determined by the scanning direction X and the direction Y perpendicular to the scanning direction X.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, the image position changing process is to effect the relative displacement, based on a deviation of angle of a first coordinate system concerning an arrangement of the pattern of mask with respect to a second coordinate system concerning an arrangement of the first images.
An exposure method according to the present invention is carried out by an apparatus comprising a plurality of illumination optical systems each for illuminating a plurality of regions M1-M5 on a mask with a pattern formed thereon, a first optical system having a plurality of projection optical systems optical axes of which are arranged in a line along a first direction Y, and a second optical system having a plurality of projection optical systems which are arranged in parallel with the first optical system and optical axes of which are arranged in a line a predetermined distance apart from that of the first optical system, in which some P1, P3, P5 of images P1-P5 of the plural regions M1-M5 and the rest P2, P4 of the images P1-P5 of the plural regions M1-M5 are projected through the first optical system and through the second optical system, respectively, onto the photosensitive substrate and in which the mask and the photosensitive substrate are synchronously scanned in a direction X approximately perpendicular to the first direction Y and in the plane of photosensitive substrate, said exposure method comprising an image position changing process for changing, by a predetermined angle, arrangement directions of the images projected through the first optical system and the second optical system relative to the first direction, changing intervals between the images P1, P3, P5 projected through the first optical system and an interval between the images P2, P4 projected through the second optical system, and changing positions of the respective images P1-P5 in a rotational direction with respect to the optical axis.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, the image position changing process is to effect the changing of arrangement directions, the changing of image intervals, and the changing of positions in the rotational direction, based on a deviation of angle of a first coordinate system concerning an arrangement of the first images with respect to a second coordinate system determined by the scanning direction X and the direction Y perpendicular to the scanning direction X.
In the case where on the photosensitive substrate, first images of the pattern of mask are preliminarily formed and second images of the pattern of mask are then to be projected for exposure as overlapping with the first images, the image position changing process is to effect the changing of arrangement directions, the changing of image intervals, and the changing of positions in the rotational direction, based on a deviation of angle of a first coordinate system concerning an arrangement of the pattern of mask with respect to a second coordinate system concerning an arrangement of the first images.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific example, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.